lockscreen: also activate lock screen windows

We are running a slightly different code path, make sure that we still
honour conventions like screen focus.

BUG: 427882

src/input.cpp

@@ -282,6 +282,12 @@ public:
         if (!waylandServer()->isScreenLocked()) {
             return false;
         }
+
+        auto client = qobject_cast<AbstractClient *>(input()->findToplevel(event->globalPos()));
+        if (client && client->isLockScreen()) {
+            workspace()->activateClient(client);
+        }
+
         auto seat = waylandServer()->seat();
         seat->setTimestamp(event->timestamp());
         if (event->type() == QEvent::MouseMove) {